The length of time any drug stays in your system varies depending on an individual's height, weight, their general health, etc.
Even their psychological state can affect the elimination of drugs, including PCP/
Also it can depend on how frequently it was used..Only once? Or more often for days or months? etc.

Generally PCP can stay in the system 1-8 days.
But if one is a chronic and/or heavy user, it can be detected in drug tests for up to 1 to 3 MONTHS.